Herman Hattaway and Michael D. Smith, "Couch, Darius Nash," American National Biography Online, February 2000, http://www.anb.org/articles/04/04-00270.html.
Couch is best remembered as an able division and corps commander in the Army of the Potomac. His career occasionally was marred by personal traits of impatience and temper directed at both subordinates and superiors. He also suffered from prolonged bouts of ill health, which led to his acceptance of the post of department commander. Although in this administrative position Couch greatly aided in the repulse of the Confederate invasion of Pennsylvania, he undoubtedly would have performed greater service as a commander in the field.